Various arrangements are provided to cover an inflatable air bag within an interior trim structure of a motor vehicle. Such interior trim structures include a panel that covers a folded air bag connected to a suitable gas generator that is activated when the vehicle is impacted.
Such arrangements are shown in various forms. In one arrangement, the folded air bag is disposed behind an interior trim panel that will break open during deployment. Examples of such arrangements are set forth in U.S. Pat. Nos. 3,756,617; 4,842,300; 5,082,310; and 5,222,760. The problem with these arrangements is that the interior trim panel must be separated along breaklines during air bag deployment. Such separation can produce undesirable delamination of an outer shell from underlying foam backing material that can cause the production of undesirable debris within the passenger compartment as the air bag deploys.
Another form of air bag closure is one in which an interior trim structure has a preformed access opening therein that is located above the folded air bag structure to allow deployment thereof from within the interior trim structure on vehicle impact. The preformed access opening is closed by a separate door assembly having an outer shell joined to a substrate that can comprise a foam backing layer and a rigid support substrate. Alternatively, the outer shell can have a less resilient outer layer and a more resilient inner layer to form a soft touch cover that overlies a relatively rigid support substrate.
Examples of these forms of prior art air bag closures is shown in U.S. Pat. Nos. 4,925,209; 5,096,221 and 5,161,819. The problem with these arrangements is that the connections between the separate door and the interior trim structure can cause delamination of the outer shell from its supporting substrate at the point of connection of the separate door structure to the interior trim panel so as to cause undesirable debris within the passenger compartment during air bag deployment. Another problem with such air bag closures is that a tether must be provided to prevent the door from impacting against an overlying windshield when the supplemental restraint system is located to protect a passenger side occupant of the vehicle.
A particular problem with separate door designs that require tethers is that the tethers have a direct mechanical connection to the door assembly. Such connections create a substantial strain on the point at which the tether is connected to the door when the door is fully opened. If the tether connection separates there is an increased possibility of windshield breakage.